Sure there are legitimate problems, but nowhere the magnitude being diagnosed and drugged.
I watch a popular forum with my HS class, and the ones on both sides. In total hundreds of people post there.
I can't remember mention of such things in HS decades ago, and I don't see any mention of it today.
IOW no mention of how many had lousy lives because they were not diagnosed and given drugs.
And no mention of their kids/grandkids being so wonderful, and what our generation missed by not getting diagnosed and drugged.
I quite agree with you that it's overdiagnosed. Not only that, but the medication alone is not sufficient; oftentimes a person (adult as well as child) needs to learn new behaviours to take advantage of the new focus the medication gives them, and that is something they can only get through non-pharmaceutical means.
Also, there are a lot of borderline cases where, if caught early enough, the child will probably respond just as well, if not better, to a regimen of lots and lots of exercise and a very structured environment - exercise can have a similar attention-focusing effect as does methamphetamine - and so that is where, IMHO, the focus should be first, not on the medication.
I think a lot of the overdiagnosis has to do with compliant doctors who accede to the demands of overly aggressive type-a parents who want to buy an unfair advantage for their kids by essentially buying a diagnosis of ADHD for the kid, thereby entitling them to demand extra accomodations from the school when it comes to things like taking tests (more time, e.g.), and some older kids will try to get the diagnosis so they can get access to the so-called "study pill" which is what ritalin is supposed to do for kids who aren't ADHD. (And some small percentage probably just want to sell the pills on the street).